Builders' Forum

Ready to start the prime coat on my MC16, have a new HVLP gun. I'm familiar with high pressure (car) painting, but not HVLP.

Using the Interlux primer, with some thinner added, and a 1.8 tip.

Seemed like I was putting out a splatter coat, but it then flowed together, in fact on the sides, it tended to run, more like orange peel. A bit heavier coat flowed well, but ran badly. I also see quite a lot of pin holes.

Before I try all kinds of experimenting, perhaps some tips and thoughts ?

I painted a stitch and glue skiff with Interlux primer and finish coat using an HVLP gun once and it worked just fine. Be sure to sand the fiberglass/epoxy and wash it with soap and water before painting. You might want to practice a bit on scrap, as these guns can lay on a lot of paint in a short time. The good news is you can move very quickly with it.

What kind of gun do you have and how many stages is the turbine? Is it a conversion gun? In order to successfully shoot marine coatings with an HVLP gun you will need to fully atomize the paint. I think a three stage turbine is the minimum and a four stage is better. You should definitely have 10lbs of pressure at the tip. Anything less will give you spatter and orange peel. Also, make sure you are generous with the thinner. The can will say don't thin past 10% but thinning 25% is the way to go and 33% is not outrageous. This violates VOC enviro rules so let your conscience be your guide. Note that the techs at Interlux specifically exclude HVLP for spraying their products.

Spraying in cooler temps is dicey. Cooler temps allow the surface to level but also gives the coating an opportunity to sag. You will have to experiment a bit to get the balance between temp, coat thickness and thinner content just right. This can be a very shallow learning curve but since you have the gun you might as well learn to do it right.